This paper provides a comprehensive overview of the proposed Mars Telecom Orbiter (MTO) mission. Launched in 2009, MTO would provide Mars-to-Earth relay services for NASA missions arriving at Mars between 2010 and 2020, enabling far higher science data return and lowering the cost for these missions. MTO also carries an optical communications payload, which will demonstrate downlink bit rates from 1 Mbps up to and possible exceeding 30 Mbps. MTO will also search for the potential Mars Sample Return orbiting sample, and will demonstrate this capability beforehand, using the sample canister, which it carries.